Can i play other characters in Batman Arkham City as well as in the Robin Edition, or only in the Robin Editio?

Would i only be able to play as robin and other characters in the robin edition of batman arkham city or can i play them in the normal one as well, whats the main differences between the two.Can i play other characters in Batman Arkham City as well as in the Robin Edition, or only in the Robin Editio?
I got Arkham City like the day after it came out, so I got Robin for challenge maps as like an early release thing. By now, you'd have to buy him on the PS Store. I THINK the Catwoman challenge maps are free, but maybe you have to buy them. You can also buy the Nightwing DLC. I have the normal one, so you can play as Catwoman, Robin, and Nightwing, but at a price. I also suggest purchasing the Arkham City Skins Pack. You get some sweet alternate Batsuits. If you wish to use the alternative suits in story mode, in the main menu after you select your save slot, press left left down down left left right up up right. I think. It might be right right up right at the end. I don't know, look it up. In conclusion, you can play as other characters in the plain, normal, Batman: Arkham City.